Chen Lin Jiang-Ming Yang Rui Cai Xin-Jing Wang Wei Wang 0009 Lei Zhang Simultaneously modeling semantics and structure of threaded discussions: a sparse coding approach and its applications. 131-138 2009 SIGIR http://doi.acm.org/10.1145/1571941.1571966 conf/sigir/2009 db/conf/sigir/sigir2009.html#LinYCWW09